Vesical imaging-reporting and data system for assessment of mpMRI response to systemic therapy for bladder cancer
Number:27ESURABS0033
Type:Scientific Electronic Presentation
Authors: Miguel Correia Da Silva, Martina Pecoraro, Marco Bicchetti, Emanuele Messina, Sara Lucciola, Valeria Panebianco
Keywords:bladder cancer; multiparametric magnetic resonance imaging; VI-RADS; neoadjuvant chemotherapy; radical cystectomy; radiological response
SECTIONS
Objectives

To define the imaging spectrum of pathological treatment response among muscle-invasive bladder cancer (MIBC) patients ultimately undergoing radical cystectomy (RC);

To explore the feasibility of a novel categorical scoring, the Neoadjuvant Chemotherapy Vesical Imaging-Reporting and Data System (nacVI-RADS) for optimal radiologic assessment of response to therapy;

To discuss possible future shifts of the current therapeutic algorithm for MIBC, including the decision between active surveillance programs, bladder-sparing modalities or to the standard of care, which may be influenced and driven by the specific nacVI-RADS criteria.


Material and methods

Between May 2019 and September 2020, 10 consecutive patients diagnosed with non-metastatic urothelial MIBC via trans-urethral resection of bladder tumor (TURBT) and/or repeated TUR (re-TURBT) were addressed to neoadjuvant chemotherapy (NAC) regimen followed by radical cystectomy and extended pelvic lymph node dissection.

All patients underwent mpMRI at 3 Tesla scan (Discovery 750; GE, Italy) both 2-4 weeks before staging TURBT and after the last NAC cycle. For each patient, the lesion with the highest VI-RADS score was considered as the index. A VI-RADS cutoff score of ≥3 to define MIBC was assumed, with score 4 and 5 identifying probability of the bladder lesion to extend into muscularis propria (T2) or through the entire bladder wall and extravesical tissues, respectively (≥T3). At this stage, the MRI acquisition parameters and reporting criteria were the same as...

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Figure 1. The proposed novel algorithm for evaluation of response to systemic therapy using the nacVI-RADS score. NAC, Neoadjuvant chemotherapy; FU, Follow-up.

Results

Patients’ characteristics and clinicopathological features are summarized in Figure 2. The mean number of NAC cycles administered was 3,5 (3 – 4) with 9 patients treated with a combination of Gemcitabine and Cisplatin (GEM-CIS) and 1 patient with a cisplatin, methotrexate, and vinblastine (CMV) regimen. All TUR specimens were classified as urothelial carcinoma of the bladder, while at RC pathology report, 1 case was found with urothelial carcinoma plus squamous differentiation.

Out of the whole sample, 3 patients were classified as nacVI-RADS 1-2 and presented with complete RaR (i.e., from VI-RADS score 5 to absence of residual disease) which was later corroborated at histopathology RC staging (i.e., ypT0 N0) with TRG score 1. Of note, 4 patients were classified as nacVI-RADS 3-4, as they exhibited partial RaR, with different RaR presentation patterns. The first...

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Figure 2. Patients’ characteristics and clinicopathological details for the case series. NAC, Neoadjuvant chemotherapy; VI-RADS, Vesical Imaging – Reporting and Data System; TUR, Transurethral resection; CHT, Chemotherapy; RC, Radical Cystectomy; TRG, Tumor regression grade; Hx, History; UC, Urothelial carcinoma; SD, squamous differentiation; GEM-CIS Gemcitabine and Cisplatin; CMV, cisplatin, methotrexate, and vinblastine.
Figure 3. Pre- and post-NAC MRI of a 69-year-old female with baseline MRI scored as an overall VI-RADS score of 3, due to lack of clear interruption of the muscularis propria. TURBT pathology results reported T2 stage HG urothelial carcinoma. Follow-up MRI after three cycles of NAC showed complete response to therapy and was scored as nacVI-RADS 1. The final histopathology confirmed a TRG-1.

Conclusions

Complete response following induction NAC with achievement of pT0 at RC is indeed critical to improve survival among MIBCs. At the same time patients who show partial or absence of response are exposed to morbidity and a delay in their effective treatment. Consequently, in such delicate decision-making algorithm, the identification of reliable predictors within clinical staging or post-NAC restaging phase evaluation is therefore a crossway in the prognosis assessment of these patients.

Recently, clinical restaging based on re-TUR sampling and tumor sequencing was found to be inaccurate. On the contrary, mpMRI can be considered as a safe tool to monitor local bladder treatment response given its high anatomical tissue layers resolution and non-invasiveness.

This case series is the preliminary evidence of the feasibility of nacVI-RADS criteria for response to therapy...

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